Most people who do not practice meditation or yoga don’t know how to properly relax their body.
The easiest way to relax your body quickly is to tense each muscle group (each part of your body) and then relax it. For example: tense your hand then relax, tense your arm then relax, tense your head then relax, same for your neck all the way down to your toes.
By consciously tensing your muscles and relaxing them you are helping your body relax deeper as you are defining tense and relaxation – and indicating to your body how you want to feel i.e. relaxed.
Do this while following the breathing pattern of deep inhales and exhales.